Taxonomia, distribuição estratigráfica e paleoecologia de ostracodes do Cretáceo Superior, Coniaciano, ao Mioceno da Bacia de Santos, Margem Continental Sul do Brasil

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The Santos basin is located the continental southern margin of Brazil. One hundred twenty two cutting samples recovered from three wells in Santos basin, two located in the shelf, 1- SPS-5A and 1-SPS-9, and one in slope, 1-SCS-9A. Relative dating based on microfossils, the lower portions of the wells 1-SPS-5A, 1-SCS-9A and 1-SPS-9 are attributed to the Coniacian, Upper Cretaceous. The upper portion of the well 1-SPS-9 range from the Lower Eocene to the Recent while, for the other two wells, the occurrences of ostracods reach only Upper Cretaceous. In the present work 27 marine and limnic species of ostracods were identified. Twenty one species are marine: Protocosta struevae Bertels, 1969, Argilloecia tenuis Ciampo, 1981, Cythereis rionegrensis Bertels, 1975, Soudanella sp. 1, Soudanella sp. 2, Soudanella sp. 3, Soudanella sp. 4, Majungaella sp. 1, Majungaella sp. 2, Protocosta sp., Buntonia sp., Brachycythere sp. Parakrithe sp. 1, ?Parakrithe sp. 2, Neonesidea sp. 1, Neonesidea sp. 2, Neonesidea sp. 3, Neonesidea sp. 4, Cytherella sp., Rostrocytheridae sp. 1, ?Rostrocytheridea sp. 2. Six species are limnic: Dolerocypris kinkoensis Grekoff, 1960, Allenocytheridea lobulata Ballent, 1980, Candona sp., ?Cetacella sp., ?Fabanella sp.,?Vernoniella sp. Eight are in open nomenclature: Gen. 1 sp., Gen. 2 sp., Gen. 3. sp., Gen. 4 sp., Gen. 5 sp., Gen. 6 sp., Gen. 7 sp., Gen 8 sp. The occurrences of Dolerocypris kinkoensis are restrict to lower Maastrichtian and corroborate previous dating. Based in the uppermost occurrences of Allenocytheridea lobulata, fossil-index of lower Maastrichtian, it was possible to approach the dating previously attributed to lower Campanian. The authochtonous occurrence of Cythereis rionegrensis is dating as late Maastrichtian, changing previous dating attributed to lower Maastrichtian. Occurrences of Protocosta struveae herein reported for Santos basin are restricted to late Maastrichtian, therefore indicating an ealier origin for this species, before considered as fossil-index of Danian. Similarly, the authochtonous ocurrence of Argilloecia tenuis in the lower Miocene seems also to indicate an earlier origin for this species usually considered middle Miocene. The above listed occurrences of marine and limnic ostracodes species, as well as charophyte oogonia, allowed an interpretation of the paleoenviromental evolution of Santos basin of the studied stratigraphic interval. The ostracode occurrences presented herein increase the potencial for correlations between strata of South Atlantic for the interval Ks-Pg.

ASSUNTO(S)

geologia estratigráfica geociencias bacia de santos (sp) geologia histórica bacias (geologia) paleoecologia

ACESSO AO ARTIGO

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